I don't think chewing gum on the protocol is good. The FDA allows the makers to say sugar free when that actually have a some amount of sugar in. In addition to that, when you chew gum, you secrete saliva and then the stomach may secrete gastric fluids and this get the stomach to prepare for food to be digested. When there is no food that comes you get hungry. And the cycle starts...chew gum...hungry...chew more gum...more hunger pains....more gum...more sugar...less ketosis.